Calculated result
Engineering evaluation Property-based flow correction complete Required glycol-solution flow (Qg) 106.7 gpm
Glycol-to-water flow ratio (rQ) 1.067 ratio
Volumetric heat-capacity ratio (rC) 1.067 water/glycol
Entered combined friction screen (Ftotal) 1.365 ratio Engineering interpretation For equal heat duty and temperature difference, the entered properties require 106.7 gpm glycol solution versus 100 gpm water.
Important limitations Use manufacturer fluid-property data at operating temperature. Recalculate pipe loss, pump curve, NPSH, coil capacity, expansion, freeze protection, and equipment limits separately. Copy results Open printable PDF Download PDF
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Understand the calculation—not just the answer 2026-08-07 · Free Library Equations & method Engineering guide Reference data & sources
Governing relationships rC = (ρw·cp,w)/(ρg·cp,g)
rQ = rC
Qg = Qw·rQ
Ftotal = Fm·rQ²
Current substitution rC = (62.4×1)/(65×0.9) = 1.067; Qg = 100×1.067 = 106.7; Ftotal = 1.2×1.067² = 1.365.
Calculation sequence
Step-by-step method Calculate water and glycol volumetric heat capacities from entered density and specific heat. Divide water by glycol volumetric heat capacity for equal-load flow ratio. Apply the entered friction multiplier and squared flow ratio only as a screening indicator. Equation legend
Inputs and calculated quantities
Qw Water-equivalent flow — gpm or L/s
ρw Water density — lb/ft³ or kg/m³
cp,w Water specific heat — Btu/(lb·°F) or kJ/(kg·K)
ρg Glycol-solution density — lb/ft³ or kg/m³
cp,g Glycol-solution specific heat — Btu/(lb·°F) or kJ/(kg·K)
Fm Entered friction-loss multiplier — ratio
Qg Required glycol-solution flow — gpm
rQ Glycol-to-water flow ratio — ratio
rC Volumetric heat-capacity ratio — water/glycol
Ftotal Entered combined friction screen — ratio Applications
How this calculation is used Building design Screen the flow correction associated with entered fluid properties.
Construction Check submitted fluid concentration and property basis.
Commissioning Relate water-equivalent and glycol flow using measured or published properties.
Quality controls
Assumptions and limitations Assumptions Entered values describe one stable operating condition and use consistent measurement boundaries. Fluid or air properties and geometric dimensions are representative of the evaluated system. Limitations This is a preliminary evaluation and field-verification tool, not a final sizing or code-compliance determination. Manufacturer data, adopted codes, project criteria, and professional engineering review remain controlling. Field use
Verification procedure Confirm the approved reference, measurement plane, and instrument calibration. Stabilize the system and record dimensions and operating data. Compare the calculated result with project documents and manufacturer data before disposition. Common engineering mistakes Using outside dimensions rather than clear inside dimensions. Combining values from different loads, device positions, or measurement conditions. Technical basis
References and source standards Need project-specific support?
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Visit SVE Group Contact the firm Engineering calculation disclaimer These engineering tools are provided for educational, preliminary evaluation, field verification, and commissioning support. Results depend on the accuracy of user-entered information and the assumptions stated for each calculation. Every colored status and comparison is a screening indicator only; project criteria, contract requirements, applicable codes, manufacturer instructions, measurement uncertainty, and authorized engineering judgment govern. The tools do not replace project-specific engineering analysis or the judgment of a licensed professional engineer.
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